Test stands such as those utilized for vehicle emissions testing can incorporate a dynamometer for applying appropriate loads to the vehicle being tested. Such loads (retarding torques) can be transmitted to the vehicle tires via spaced-apart rollers which support the drive wheels of the vehicle. In order to facilitate testing, the dynamometer is typically placed in a recess or pit in the surface of the floor so that the vehicle can be driven directly onto the spaced-apart rollers. Because the dynamometer is confined within the recess or pit, and since the dynamometer might be of the eddy current type which generates a significant amount of heat, cooling of the dynamometer is necessary. Such cooling is typically accomplished by fan blades on the rotating member of the dynamometer which cause air to enter and exit the dynamometer housing. It has been found that the volume of air drawn into and expelled from the dynamometer through the use of such fan blades is not sufficient to effectively cool the dynamometer since a substantial portion of the dynamometer is confined within a pit or recess in the floor. A considerable portion of the hot air being discharged from the dynamometer recirculates within the pit or recess and is subsequently drawn back into the air inlet of the dynamometer and reheated resulting in a drastic reduction in the thermal dissipation capacity of the dynamometer. In order to circumvent these problems, an auxiliary blower system is typically attached to an inlet manifold on the dynamometer to increase the amount of air passing therethrough and to ventilate the pit or recess to prevent recirculation. The use of such a blower system, however, significantly increases the overall cost of the vehicle test stand.